Magnetic separation of piled magnetic sheets



Nov; 18, 1958 K. H. GULICK 2,860,874

MAGNETIC SEPARATION OF FILED MAGNETIC SHEETS Filed June "16, 1955 2 Sheets-Sheet 1 FIG 2 INVENTOR.

KENNETH hf GUL lCk ATT S Nov. 18, 1958 K. H. GULICK 7 2,360,374

MAGNETIC SEPARATION OF PILED MAGNETIC SHEETS Filed June 16, 1955 2 Sheets-Sheet 2 F/G. 3 I

38 J6 L,- ,'\J

I ,40 E f F/G 4 IN V EN TOR.

KEN/V5777 H GUL/CK MAGNETIC SEPARATION OF PILED MAGNETIC SHEETS Application June 16, '1955, Serial No. 515,944

13 Claims. (Cl. 271-10) This invention relates to improvements in magnetic separation of piled magnetizable sheets. The invention has to do primarily with piled ferrous metal sheets, although it is applicable to other less frequently encountered materials and alloys having magnetic qualities.

The preliminary separation of the uppermost sheets of a pile of iron or steel sheets by magnetizing them with permanent magnets or electromagnets is known and conventional. In pile feeders for such sheets as previously built magnets are supported along the sides of the pile and sometimes at the rear end of the pile. In order to obtain the best results, that is the best magnetization of the uppermost sheets of the pile, horizontally disposed magnets should stand with about half their height or width above the top level of the pile. When the magnetic poles are spaced vertically the most effective sheet separation is accomplished when the top sheet of the pile is about one-third of the way down from the top of the magnet. In either case the upper portions of the magnets are materially above the top of the pile when the most effective separation is obtained. This fact makes it inadvisable to use magnets at the front end of the pile, because if they were to be so used the sheets as they were fed off the pile would need to have their front ends raised materially so as to clear the magnets.

The conventional way of handling and forwarding metal sheets is by means of a pair of transversely spaced suckers. They are positioned a short distance behind the front edge of the sheet. The sheets are generally of thin gauge and large area, and if they were to be raised materially by the suckers the portions forward of the suckers would tend to bend and sag and at times strike against the magnets. This can cause the sheets to be dropped by the suckers or, if only one corner stumbles, the-sheet may be fed at an angle. Furthermore raising the sheets before forwarding them would seriously limit the top speed of a high speed feeder. As a consequence of these difiiculties feeders for metal sheets as previously constituted have employed no magnets at the front end of the pile.

The principal object of the present invention is the provision of magnetic sheet separating means which shall be capable of effective use at the forward end of a pile of magnetic sheets. Another object is the provision of front magnet means which shall do away with the necessity for raising materially the front end of the top sheet of the pile before it is fed forward off the pile.

Another object is the provision of front end magnet means which has an open space at the level of the top of the pile through which the sheet being fed may pass with a minimum of upward movement.

A further object is the provision of pairs of magnets spaced apart vertically, the top of the lower magnet and the bottom of the upper magnet of each pair being below and above the top of the pile respectively, for effecting magnetic separation of the front edges of the uppermost sheets, whereby an open space is provided between the magnets at the top level of the pile through which sheets "States Patent may be fed horizontally while requiring little or no rais'-' lllg- Other objects and features of novelty will appear as 1 proceed with the description of those embodiments of theinvention which, for the purposes of the present ap-' plication, I have illustrated in the accompanying draw ings, in which Fig. 1 is a somewhat diagrammatic isometric view of a pile feeder embodying the invention. 1

Fig. 2 is afragmentary side elevational view illustrating one arrangement of magnets which may be employed in connection with the invention, and

Figs. 3, 4 and 5 are diagrammatic elevational views looking forward from a vertical plane corresponding to the line 35 of Fig. l and illustrating other arrangements of magnets which may be utilized for carrying out the invention.

As sheet metal feeders of the type with which this invention is to be used are known in the art, only so much of the feeder is herein illustrated as is believed necessary for a complete understanding of the invention by those skilled in the art.

Referring to Fig. l, a pile of sheets 10 responsive to magnetic lines of force is carried on a pile support 11 of a pile feeder for metal sheets. The pile support comprisesside arms 12 and 13 which may be I-beams connected at their forward ends by a crossbar 14 which is shown as of channel shape. Each of the arms 12 and 13 is provided with a pair of brackets 15 near its ends, one only being illustrated on each side, these brackets being supported by cables 16 of the pile feeder. It is to be understood that the pile support 11 is provided with conventional means for raising it intermittently during automatic feeding in response to control by pile height governing means (not shown) to maintain the top of the pile at a predetermined level.

After the uppermost sheets of the pile are preliminarily separated by magnetic means, as will presently appear, the top sheet of the pile is lifted slightly by conventional lifting suckers 17 andtransferred to forwarding suckers 18. The top sheet is then fed horizontally by the for warding suckers 18 in the direction of arrow 19 to the bight of conventional pullout rolls. If desired, the lifting suckers 17 may be eliminated, since the top sheet will be approximately at the line of feed. As illustrated herein the pullout means comprises a shaft 20 driven continuously from the machine being fed. Shaft 20 carries two or more rolls 21. Freely rotatable upper rolls 22 are carried by arms 23 which are swung down to cause rolls 22 to contact driven rolls 21 during a part of each cycle. The rolls 22 assist the lower rolls 21 to impart traction to the sheet. The pullout rolls 2 1, 22 take over the forwarding action as the suckers 18 release the sheet and feed it either to a conveyor or directly to the sheet treating machine to which sheets are to be fed.

As is customary in pile feeders for magnetizable sheets, magnets 24 may be arranged alongside the top of the pile for effecting preliminary separation of the uppermost sheets of the pile. These magnets may be supported from the frame of the feeder (not shown) by any suitable means. Preferably they should stand at such a level that the uppermost sheet of the pile will intersect the magnets half way between their tops and bottoms. Brass or other non-magnetic guide plates 25 may be secured to the magnets on the sides facing the pile. They may have outwardly deflected lower ends which may assist in guiding the uppermost sheets as the pile is initially brought into position for the feeding of sheets therefrom.

At the rear end of the pile there are provided magnets 26 with guide plates 27. These magnets may be an ranged horizontally like the magnets 24, or may have their *poles disposed one above the other as herein illustrated,

These magnets 26 in addition to functioning as preliminaryseparatingmeans also serve to hold-or'restrain-the sheets next beneath the top sheet as the latter is drawn forward by the suckers 18.

-At -the front *end- -of: the -pile preliminary-separation of the uppermost sheets iseffected in a novel manner-by providing a physically unobstructed magnetic-fieldwhich may be-created by one -or more;pairs--of-magnets -arranged-one magnet above theother. -'-In the'form shown in Fig. 2 one pair comprises anuppermagnet 29 and a lower magnet 30. In this case the magnets are disposed vertically and the north;pole"of magnet-29 is adjacent the south pole ofymagnet 30. The distance between theadjacent polesyof' the two-different magnets is less than the distancebetween the-oppositepoles: of each magnet. Consequently 'the magnetic-field 'between the two magnets is StIOIIgKHdfltfUDClZl'OHS to eifectively separate the front dgSOf 'th magnetic sheets. Although the arrangement illustrated, that is with opposite" poles adjacent each other, is preferred; that-arrangement is not essential. In other words an arrangement'in which like poles of the two' magnets are'disposed adjacent each other will, also eflfect good preliminary separation of the uppermost sheets of the pile. The great advantage of the pairs of magnets above and below theft-op level of the pile is that their spacingapart vertically'provides an open space at the top level of the pile through which the sheets may be fed one after another Without requiring lifting.

Below the magnet 29 and preferably fastened toit'there is a brass or other non-magnetic guide plate 31 disposed horizontally, while on the rear sidev of magnet'30 there is a guide plate 32 of non-magneticmaterial with a horizontally disposed upper portion 33 spaced somewhat from the guide plate 31. These guide plates serve to direct a sheet being fed off the pile into the bight of pullout rolls 21 and 22. If desired one or both of these plates 31, 32 may carry antifriction means for facilitating the movement of the sheet being fed. Asjillustrated herein this antifriction means may consist of a ;small roller 34 carried by plate 31 and projecting through a slot in the plate slightly below the lower surface of the plate.

In Fig. 3 of the drawings magnets 35 and;,36 are horseshoe magnets which are arranged horizontally instead of. vertically as in the Fig. 2 form of the invention, the magnets 35 and 36 of each pair being mounted respectively above and below. the top level 37 of the pile and somewhat closer together than the distance between the opposite poles of each individual magnet. .In this case also the unlike poles of adjacent magnets 35 and 36 are disposed opposite each other.

In Fig. 4 there are two pairs of magnets 38, 39 disposed respectively above and below the level 40 of the pile. Here however like poles of the magnets38, 39 are disposed opposite each other. While three pairs of magnets 38, 39 could be employed there maybe instances where it will be more convenient to arrange the intermediate pairs of magnets 41, 42 vertically instead of horizontally and they are thus illustrated in this form of the invention. Where like poles of superposed magnets are arranged opposite each other, as ,in this figure, it is evident that the forward edge portions of the uppermost sheets near each pole will be correspondingly magnetized, so that those portions of adjacent sheets .Will repel each other.

,In Fig. upper ,magnets. 44 are disposed abovev the level 45 of the top of the pile and: lower magnets 46 are disposed beneath the level-45, in staggered relation. In this case the positive poles of one set of magnets .are arranged opposite the negative poles of the other.set, so that the magnetic action is presumably similart to that ofFigs. 2 and 3.

In ,all forms f the invention heretofore described the same principle-obtains, namely thatmagneticqpoles above and below the level of the top of the pile at its forward end with openspace .between .the .poles effects sheet. separation without interposingany obstacle to the feeding off of the top sheet and without requiring any substantial raising of the sheet. Two magnets spaced apart vertically create a magnetic field between them, much the same as the opposite poles ofa single magnet create a field betweenthem. Byspacing two magnets vertically, applicant of course takes-advantage of the omission of iron between the poles adjacent the top of the pile, which iron-would presentan-obstacle to the forwarding of the sheets.

While in the forms of the invention shown permanent magnetshave ,been :illustrated, it should be understood that electromagnets may be used to accomplish the same results.

Having thus described my invention, I claim:

1. The method of feeding magnetizable sheets from a pile thereof,:which comprises. positioningin front of the-for-ward end of the pile .magnet means above the level-of the .pile, positioning a second..magnet imeans below the pile level witha space .therebetween, whereby the uppermost sheets :are magnetically separated, and feedingoff the top sheet through the space :between said magnet-means. ZJThe method of feeding magnetizable sheets from a-=pile' thereof, which comprises positioning in front .of the forward end of the pile a pair of permanent magnets one spaced above the other, whereby the uppermost sheets are magnetically separated, and feeding off the top sheet through thespace between said magnets.

3. The method of feeding magnetizable sheets from a-pile'as defined in claim 2, which comprises arranging said magnets with the poles of each magnet one above the other.

4."In apparatus for feeding magnetizablesheets one after another from the top of a pile of such sheets, a plurality of-magnets in front of the forward end of the pile partly close above and partly close below the path of sheet feed for creating a magnetic field for separating the front edges of said sheets, there being a space hetweenthe portions of said means above and the portions of said means below said path of feed for permitting unobstructed travel of sheets between said por- 'tl'Ol'lSyQIldIllGflHS for feeding sheets one at a timethrough said unobstructed space.

5. Apparatus substantially as defined in claim 4, comprising a-non-magnetic guiding plate beneath the upper magnet and a non-magnetic guiding plate above the lower magnet, between which guiding plates the sheets are directed as they are fed off the pile by said feeding means.

6. Apparatus substantially as defined in claim 5,-wherein one 'of, said non-magnetic plates carries antifriction means projecting slightly-beyond the surface ofthe plate into the pathof travel of the sheet being fed off the pile.

'7. Apparatus substantially as defined in claim 6, wherein said antifriction means is carried by the upper non- ,magnetie'plate and projects downward slightly beneath the lower surface thereof.

8. Apparatus substantially as defined in claim 4, comprising magnet. means at the rear end of the pile for attracting and restraining the uppermost sheets of the pile beneath the top sheet thereof while .the latter sheet is being advancedby said feeding means.

9.,Apparatus substantially as defined in claim 4, com- ,prising magnet means at both sides of the pile for separating the side edges of the uppermost sheets and for thereby .aidingand facilitating the forwarding of the top sheet by said, feeding means.

10..In apparatus for feeding magnetizable sheets .one afteranother from the top of a pile of suchsheets, a

plurality of transversely spaced magnets disposed below the top of the pile in advance of the forward end thereof, a plurality of magnets above the first named magnets and above the top of the pile, said magnets serving collectively to magnetically separate the forward edges of the uppermost sheets of the pile, a plurality of magnets along each side of the pile disposed partly beneath and partly above the uppermost sheets of the pile for separating the side edges of the uppermost sheets, and sucker means for feeding oil the top sheet through the space between the upper and lower magnets at the forward end of the pile.

11. Apparatus substantially as defined in claim 10, comprising magnet means at the rear end of the pile for attracting and restraining the uppermost sheetsbeneath the top sheet While the latter sheet is being advanced by said sucker means.

12. Apparatus for feeding magnetizable sheets substantially as defined in claim 4, wherein said sheet feeding means comprises a pair of suckers, said apparatus comprising a pair of pullout rolls disposed in front of the pile with their bight at substantially the same level as the top of the pile, said rolls being timed to take each sheet at approximately the same time that the vacuum in said sucker forwarding means is broken.

13. In apparatus for feeding magnetizable sheets one after another from the top of a pile of such sheets, a plurality of transversely spaced magnets disposed below the top of the pile in advance of the forward end thereof, a plurality of magnets above the first named magnets and above the top of the pile, all of said magnets serving collectively to magnetically separate the forward edges of the uppermost sheets of the pile, and means for feeding off the top sheet at the pile level through the space between the upper and lower magnets at the forward end of the pile.

References Cited in the file of this patent UNITED STATES PATENTS 1,716,602 Ross June 11, 1929 1,870,336 Lincoln Aug. 9, 1932 2,474,141 Chatterton June 21, 1949 2,650,824 Fowler Sept. 1, 1953 

